2012-05-18 20:54:51 +00:00
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===========================================
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Hard Disk and File System Recommendations
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===========================================
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2012-05-03 03:31:35 +00:00
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2013-06-07 16:51:05 +00:00
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.. index:: hard drive preparation
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2012-09-06 00:21:04 +00:00
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2013-06-07 16:51:05 +00:00
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Hard Drive Prep
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===============
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Ceph aims for data safety, which means that when the :term:`Ceph Client`
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receives notice that data was written to a storage drive, that data was actually
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written to the storage drive. For old kernels (<2.6.33), disable the write cache
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if the journal is on a raw drive. Newer kernels should work fine.
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2012-05-03 03:31:35 +00:00
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2012-05-03 17:15:21 +00:00
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Use ``hdparm`` to disable write caching on the hard disk::
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2012-05-03 03:31:35 +00:00
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2012-08-28 18:02:13 +00:00
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sudo hdparm -W 0 /dev/hda 0
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2012-05-03 03:31:35 +00:00
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2013-06-11 19:10:52 +00:00
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In production environments, we recommend running a :term:`Ceph OSD Daemon` with
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2013-06-07 16:51:05 +00:00
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separate drives for the operating system and the data. If you run data and an
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operating system on a single disk, we recommend creating a separate partition
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for your data.
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2012-05-03 17:15:21 +00:00
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2013-06-07 16:51:05 +00:00
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.. index:: filesystems
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2012-09-06 00:21:04 +00:00
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2013-06-07 16:51:05 +00:00
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Filesystems
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===========
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2012-09-06 00:21:04 +00:00
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2013-06-07 16:51:05 +00:00
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Ceph OSD Daemons rely heavily upon the stability and performance of the
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underlying filesystem.
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2012-10-29 20:01:06 +00:00
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2016-04-12 17:24:56 +00:00
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Recommended
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-----------
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We currently recommend ``XFS`` for production deployments.
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Not recommended
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---------------
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2017-06-30 17:54:18 +00:00
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We recommand *against* using ``btrfs`` due to the lack of a stable
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version to test against and frequent bugs in the ENOSPC handling.
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2016-04-12 17:24:56 +00:00
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We recommend *against* using ``ext4`` due to limitations in the size
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of xattrs it can store, and the problems this causes with the way Ceph
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handles long RADOS object names. Although these issues will generally
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not surface with Ceph clusters using only short object names (e.g., an
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RBD workload that does not include long RBD image names), other users
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like RGW make extensive use of long object names and can break.
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Starting with the Jewel release, the ``ceph-osd`` daemon will refuse
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to start if the configured max object name cannot be safely stored on
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``ext4``. If the cluster is only being used with short object names
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(e.g., RBD only), you can continue using ``ext4`` by setting the
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following configuration option::
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osd max object name len = 256
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osd max object namespace len = 64
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.. note:: This may result in difficult-to-diagnose errors if you try
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to use RGW or other librados clients that do not properly
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handle or politely surface any resulting ENAMETOOLONG
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errors.
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